Hingson and Howland (2002) estimated that 1,138 college students die from alcohol-related[unreadable] traffic crashes annually. An additional 307 college students die annually from alcohol-related non-traffic[unreadable] unintentional injuries and 500,000 college students annually sustain alcohol-related injuries (Hingson and[unreadable] Howland 2002). Caffeinated alcoholic beverages target young adults with the promise that the caffeine will[unreadable] counteract the sedating effects of alcohol and thus let the consumer remain alert and active longer, while[unreadable] continuing to drink. If young people erroneously believe that caffeine in beer will protect them from alcohol-related[unreadable] injury, then such beverages may increase mortality and morbidity in this population. Thus, it is[unreadable] important to have accurate information about the extent to which such beverages affect impairment both[unreadable] acutely and residually. Such information could correct misunderstandings young people have about the[unreadable] relative safety of caffeinated beer and thereby reduce injury. The study could have implications for safety-sensitive[unreadable] occupations as well. It is common for people to use caffeine to counteract the sedative effects of[unreadable] alcohol. If, however, the alcohol and caffeine interact to yield greater impairment in next-day performance,[unreadable] workers should be aware of this, particularly if their jobs have low tolerance for error. This study, to our[unreadable] knowledge, will be the first to compare the acute and residual effects of caffeinated and non-caffeinated beer[unreadable] on driving performance.[unreadable] Objectives: The aim of this study is to develop information about the acute and residual effects of a new[unreadable] product being targeted to young adults. It is important to understand the effects of caffeinated alcoholic[unreadable] beverages early on in the marketing campaign so that if they pose a greater threat to pubic health than[unreadable] traditional alcoholic beverages, (1) consumers can be educated and (2) policy-making can be informed with[unreadable] accurate information. We will compare the acute and residual effects on driving impairment of caffeinated[unreadable] and non-caffeinated beer to each other and to placebo when participants have received sufficient alcoholic[unreadable] beverage to attain a blood alcohol concentration (BAC) of .12 g%.[unreadable] Study Design: We will conduct a placebo-controlled trial using a 2 X 2 mixed-model study design. The[unreadable] within-subjects factor will be alcohol vs. placebo; the between-subjects factor will be caffeinated vs. noncaffeinated[unreadable] beer.[unreadable] Setting: The study will take place at the General Clinical Research Center at Boston Medical Center.[unreadable] Participants: We will recruit 144 students from Boston area Universities.[unreadable] Outcome Measures: Acute and residual driving impairment will be assessed using a driving simulator and[unreadable] an objective measure of sustained attention/reaction time, the Psychomotor Vioilance Test (PVT).[unreadable]